[pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

Author: pre-commit-ci[bot]

src/tox/config/loader/api.py

@@ -157,7 +157,7 @@ def load(
                 elif isinstance(converted, SetEnv) and isinstance(converted_override, SetEnv):
                     converted.update(converted_override, override=True)
                 elif isinstance(converted, PythonDeps) and isinstance(converted_override, PythonDeps):
-                    converted += converted_override   # type: ignore[operator]
+                    converted += converted_override  # type: ignore[operator]
                 else:
                     msg = "Only able to append to lists and dicts"
                     raise ValueError(msg)